Assembly for a Device of a Fiber Web Production Line

ABSTRACT

An apparatus having a rod or a blade ( 21 ) for a device of a fiber web production line, especially a rod-bed or a blade holder or holder assembly for a rod or a blade ( 21 ) of a device for coating or sizing a fiber web, particularly a paper or a board web, which assembly comprises a holder ( 25 ), in which the rod or the blade ( 21 ) is supported on the front side of the holder ( 25 ), and which assembly has loading means ( 24 ). The assembly further comprises sensors, in particular piezo sensors ( 10 ) located between the rod or the blade ( 21 ) and the loading means ( 24 ) for measuring the loading pressure of the rod or the blade ( 21 ) locally.

CROSS REFERENCES TO RELATED APPLICATIONS

This application claims priority on European Application No. EP13162894, filed Apr. 9, 2013, the disclosure of which is incorporated byreference herein.

STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSOREDRESEARCH AND DEVELOPMENT

Not applicable.

BACKGROUND OF THE INVENTION

The present invention relates to an assembly comprising a rod or a bladefor a device of a fiber web production line, especially to a rod-bed ora blade holder assembly for a rod or a blade of a device for coating orsizing a fiber web, particularly a paper or a board web, especially arod-bed or a blade holder or holder assembly for a rod or a blade of adevice for coating or sizing a fiber web, particularly a paper or aboard web, which assembly comprises a holder in which the rod or theblade is supported on the front side of the holder, and which assemblyhas a loading device.

As known from the prior art in fiber web producing processes typicallycomprise an assembly formed by a number of apparatuses arrangedconsecutively in the process line. A typical production and treatmentline comprises a head box, a wire section and a press section as well asa subsequent drying section and a reelup. The production and treatmentline can further comprise other devices and sections for finishing thefiber web, for example, a sizer, a calender, a coating section. Theproduction and treatment line also comprises at least one winder forforming customer rolls as well as a roll packaging apparatus. In thisdescription and the following claims by fiber webs are meant for examplepaper and board webs.

In production of fiber webs, for example of paper or board webs, sizingis used to alter the properties of a fiber web by adding sizing agents(sizing medium), for example glue chemicals. Sizing can be divided tointernal sizing and surface sizing. In internal sizing the sizing agentis added to pulp in the wet end of the fiber web machine before forming.In surface sizing the sizing agent is added onto the surface of thefiber web at the fiber web machine.

In production of fiber webs, for example of paper or board webs,coating, especially the surface of a fiber web is formed with a layer ofcoating paste (coating medium) at a coating station followed by drying.The coating process can be divided in supplying the coating paste ontothe web surface, which is called the application of the coating paste,as well as in the adjustment of the final amount of coating paste.

The coating or the sizing of a fiber web typically utilizes a coatingdevice—a coater—or a sizing device—a sizer. In connection with thecoaters and sizers different kinds of application technology forapplication of the coating medium or the sizing medium on the fiber webare employed, for example curtain technology or blade coating technologyor film transfer technology or rod coating technology or air brushcoating technology or spray coating technology.

In the coating or sizing based on rod technology, rod-bed assemblies areused for the rod functioning as a dosing element of the coating orsizing medium for scraping off the excessive medium quantity of thesizing or coating medium. In the sizing the rod functions against a rolland in the coating the rod functions against the fiber web. The rodcoating or sizing assembly is composed of a rod and of a rod-bedcomprising a holder to which the rod is attached directly or by means ofan insert that is fitted into the holder for the rod. The rod-bed is inturn attached to a beam or corresponding support structure arranged onthe frame of the machine.

A web of paper or paperboard can be coated or surface sized usingfilm-transfer or blade technology, wherein the web being treated ispassed through a nip between two opposed rolls. The coating or sizingmedium is applied with the help of a suitable applicators to the surfaceof one or both of the nip-forming rolls, wherefrom the substance istransferred to the surface of the web being treated in the nip betweenthe rolls. The thickness and cross-machine profile of the coating orsizing medium layer applied to the roll surface are controlled by ablade or rotatable rod.

In the coating or sizing based on blade or film transfer technology theblade or rod is attached to a holder. The holder with accompanyingsupport and fastening means is in turn attached to a beam orcorresponding support structure arranged on the frame of the machine.

Typically the beam or corresponding support structure of acoating/sizing rod/blade is arranged movable by loading means arrangedat each end of the beam or corresponding support structure by which themain loading of the blade or rod is provided. In the cross direction ofthe web to be coated or sized the loading of the blade or rod istypically arranged by profiling loading means for example by spindlesthat load cross-directional means for example a loading hose (ahose-loaded blade) and/or by a rigid loading plate, which spindles arespaced apart at certain intervals at the cross direction of the fiberweb to be coated or sized.

In a hose-loaded blade or rod in a fiber web machine in coating orsizing devices, the contact force of the blade or rod on the opposingsurface is increased by means of loading hoses acting on the blade orrod holder. Loading hoses normally have an oval cross-section. Theloading hose is set between the holder and its support.

In coating and sizing utilizing the dosing of the coating or sizingmedium, especially the quality and profile of the medium is controlledby automatically or manually controlling the surface pressure created bythe rod or the blade by means of the loading means and the profilingloading means. The surface pressure between the rod or the blade and thecounter roll is not directly measured but instead the adjustments neededare done based on measurements of the fiber web and its coating/sizinglayer.

The rod or the blade are loaded by adjusting pressure of a loading tubethat is supported on a frame of the holder or by adjusting the rigidloading plate supported on a frame of the holder. The loading pressesthe back of the holder and the rod or the blade towards the web to becoated or towards the corresponding coating or sizing roll, in order tobuild up the contact pressure of the rod or the blade against the web oragainst the roll. In many loading tube arrangements there is also aloading plate or corresponding support plate on the back side (on theopposite side in respect of the holder) of the loading tube that islocally loaded by loading elements, for example by spindles that arespaced apart at certain intervals at the cross direction of the fiberweb to be coated or sized. There are also loading constructions in whichno loading hose is used and instead the loading is arranged by means ofthe loading plate and the spindles. The spindles are adjusted manuallyor automatically based on a scanning measurement device located afterthe coater or the sizer. Thus there is no knowledge of the actual valueof the loading pressure of the rod or the blade locally.

The lack of knowledge of the actual values makes the automatic controldifficult and unreliable to use as typically the profile informationreceived from the measurement device, for example from a scanningmeasurement frame is unreliable and not exact enough for profileadjustment of coating or sizing in desired accuracy.

By using manual control a required quality level of coating or sizing istypically achieved but locally the pressure may vary considerably, whichmight locally cause wear in rod and other surfaces.

As a summary one of the main problems is that the actual and realknowledge of the local loading information of the rod or the blade isnot available and thus the adjustments and control of coating or sizingmust be done based on indirect information.

Many of the above problems and disadvantages occur in coating and sizingirrelevant of the technology type used even though they have been insome cases described in reference to one example only.

In WO 2010099830 is disclosed a blade for doctoring a moving surface orfor sizing or creping a fiber web produced or finished in a web machine,especially in a paper, board or tissue machine, which comprises at leastone fiber optical waveguide being arranged on a surface of the blade orembedded in the material of the blade. Disadvantageous of thisarrangement is that during use the blade wears and thus at regularintervals a new blade must be changed. A blade with a fiber opticalwaveguide is expensive thus the changing costs increase. In cases wherethe fiber optical waveguide is arranged on the surface of the blade alsothe waveguide may wear and thus its signal level may change and on thesurface the waveguide is susceptible to damage.

In US 2005223513 is disclosed a calibration device for the pressure of ascraping device blade, which abuts the periphery of a roll or acylinder, in particular of a paper machine, a printing machine, acalender or the like, comprising a holding blade, a sensor holdermounted thereto, and a pressure sensor, for example a piezo element arepositioned such that the position of the pressure sensor on theperiphery of the roller or cylinder corresponds to the position ofabutment of the blade. Disadvantageous of this arrangement is that it issuitable for calibrating and testing in service situations but it is notsuitable to be used during process. Further, as in the above case thesensor mounted on the blade increases the changing cost of the blade,which as a wear part changed regularly should be cost effective.

SUMMARY OF THE INVENTION

An object of the present invention is to create an assembly comprising arod or a blade for a device of a fiber web production line in which thedisadvantages of devices known from prior art are eliminated or at leastminimized.

Yet another object of the present invention is to provide a rod-bed or ablade holder for a rod or a blade of a device for coating or sizing afiber web, particularly a paper or a board web, in which the actualvalue of the loading pressure of the rod locally is received.

In this description and the claims, by front side of the holder is meantthe side on which the rod or the blade is located i.e. the side that isfacing the web to be treated or the roll onto which the coating orsizing medium is applied and corresponding by the back side the side onwhich the loading means are located and which is facing the beam orcorresponding support structure on which the holder is attached.

In order to achieve the above objects and to solve the problems of priorart mentioned above and coming apparent later an assembly comprising arod or a blade for a device of a fiber web production line, especiallyto a rod-bed or a blade holder assembly for a rod or a blade of a devicefor coating or sizing a fiber web, particularly a paper or a board webaccording to the invention is mainly characterized by sensors, inparticular piezo sensors, located between a rod or a blade and a loadingmeans for measuring the loading pressure of the rod or the bladelocally.

According to the invention the assembly comprises a holder, in which arod or a blade is supported on the front side of the holder, and loadingmeans and sensors, in particular piezo sensors, located in the holderbetween the rod or the blade and the loading means for measuring theloading pressure of the rod or the blade locally. Advantageously thesensors are located spaced apart at certain intervals at the crossdirection of the fiber web to be coated or sized.

According to an advantageous feature of the invention across-directional profile of the loading pressure is provided based onthe measurement information and based on the profile information theloading means are adjusted manually or automatically to load such thatdesired profile is provided in coating or sizing.

According to an advantageous feature the loading means comprise mainloading means and profiling loading means.

According to an advantageous feature the sensors, in particular piezosensors, are located in the holder between the rod or the blade and theprofiling loading means for measuring the loading pressure of the rod orthe blade locally.

According to an advantageous aspect of the invention the rod-bedassembly comprises a holder, an insert removably and insertablysupported in a groove of the holder and in which rod-bed assembly a rodof a coating or sizing or device is rotatably supported in a recess onthe front side of the insert, which rod-bed assembly further comprisessensors, in particular piezo sensors, located in between the insert andthe holder on the opposite side of the insert in respect of the rodlocated in the insert for measuring the loading pressure of the rod.

According to another advantageous aspect of the invention the rod-bedassembly comprises a holder, in which a rod of a coating or sizing ordevice is rotatably supported in a recess on the front side of theholder, which rod-bed assembly further comprises sensors, in particularpiezo sensors located on the back side of the holder in respect of therod for measuring the loading pressure of the rod.

According to another advantageous aspect of the invention the bladeholder assembly comprises a holder and a blade supported in the holder,which assembly further comprises sensors, in particular piezo sensors,located between the blade and the loading means for measuring theloading pressure of the blade.

According to an advantageous feature in cases where the blade holderassembly comprises a loading hose and its loading means, the sensors, inparticular the piezo sensors are located between the blade and theloading hose and/or between the loading hose and its loading means.

According to another advantageous feature in cases where the bladeholder assembly or the rod-bed assembly comprises a rigid loading orsupport plate and its loading means, the sensors in particular the piezosensors, are located between the blade or the rod and the rigid loadingor support plate and/or between the loading or support plate and itsloading means.

According to an advantageous feature of the invention the sensors, inparticular piezo sensors are located spaced apart in the cross directionof the web to be coated or sized desired intervals.

According to an advantageous feature of the invention the sensors, inparticular piezo sensors, are located in a band comprising a number ofspaced apart sensors.

According to an advantageous feature of the invention the sensors, inparticular piezo sensors, are located in the loading direction of therod or the blade in line with the rod or the blade.

The assembly comprises as loading means a loading tube and spindlesloading the loading tube located on the opposite side in respect of therod or the blade placed in the holder of the assembly i.e. on the backside of the holder. According to an advantageous feature the assemblyhas means for transmitting the measurement results of the sensors, inparticular piezo sensors, to control means for controlling the loadingmeans, in particular the spindles for regulating the pressure of theloading tube. The sensors are located aligned with the spindlescorrespondingly spaced apart.

According to an advantageous feature the assembly according to theinvention is used as an upgrade kit of the assembly, in which theupgrade kit comprises as an expert service arranged measurement with theassembly and adjustment of the loading means to load the rod or theblade to provide the desired profile.

The assembly according to the invention is applicable in connection withcontinuous measurements or as troubleshooting equipment or during astart-up of a new device. By the invention many advantages are achievedthe profiling of the dosing of the coating or sizing medium by the rodor the blade is improved. The locally existing peaks of loading can alsobe avoided and thus the wear of the rod or the blade, the rod-bed or theholder and the coating or sizing roll is decreased and thus the servicetime of the same increased.

In case the invention is used in connection with a start-up of a newdevice by utilizing the invention the required quality level is achievedfast and thus the production can begin in a shorter time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is schematically shown an example of the invention in connectionwith a rod-bed assembly comprising an insert,

FIG. 1B is schematically shown an example of the invention in connectionwith a rod-bed assembly without an insert,

FIGS. 2A and 2B are schematically shown examples of the invention inconnection with a blade holder assembly,

FIG. 3 is schematically shown an example of loading and profilingarrangement in a coater or in a sizer

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following the invention is described referring to the examples ofFIGS. 1A-3 to details of which the invention is not to be narrowlylimited. In the figures and the description by the same reference signsare indicated corresponding parts and part components unless otherwisementioned.

In FIG. 1A is schematically shown an example of the invention inconnection with a rod-bed assembly. The rod-bed assembly comprises aholder 13, and an insert 12 removably and insertably supported in agroove 14 of the holder 13. In which rod-bed assembly a rod 11 of acoating or a sizing device is rotatably supported in a recess 15 on thefront side of the insert 12, which rod-bed assembly further comprisessensors, in particular piezo sensors 10, located in between the insert12 and the holder 13 on the opposite side of the insert 12 in respect ofthe rod 11 located in the insert 12 for measuring the loading pressureof the rod 11. The sensors, in particular the piezo sensors 10 transmitmeasurement information to a receiver 31, which transmits themeasurement information to a control system 32, which can directly orindirectly control the loading means (FIG. 3) of the rod-bed assembly.

In FIG. 1B is schematically shown an example of the invention inconnection with a rod-bed assembly. The rod-bed assembly comprises aholder 13 and in which a rod 11 of a coating or a sizing device isrotatably supported in a recess on the front side of the holder 13,which rod-bed assembly further comprises sensors, in particular piezosensors 10 located on the back side of the holder 13 on the oppositeside in respect to the rod 11 for measuring the loading pressure of therod 11. The sensors, in particular piezo sensors 10 transmit measurementinformation to a receiver 31, which transmits the measurementinformation to a control system 32, which can directly or indirectlycontrol the loading means (FIG. 3) of the rod-bed assembly.

In FIGS. 2A and 2B are schematically shown examples of the invention inconnection with a blade holder assembly and the blade holder assemblycomprises a holder 25 and a blade 21. The assembly further comprisessensors, in particular piezo sensors 10 located between the blade 21 anda loading means, for measuring the loading pressure of the blade 21. Thesensors, in particular piezo sensors 10 transmit measurement informationto a receiver 31, which transmits the measurement information to acontrol system 32, which can directly or indirectly control the loadingmeans 24 shown in FIG. 3 of the rod-bed assembly.

In the example of FIG. 2A in the blade holder assembly the loading meansis a loading hose 24 and the sensors are piezo sensors. The sensors 10are located between the blade 21 and the loading hose 24 and/or betweenthe blade and the loading means behind the loading hose 24 in the holder25. The sensors, in particular piezo sensors 10, transmit measurementinformation to a receiver 31, which transmits the measurementinformation to a control system 32, which can directly or indirectlycontrol the loading means of the blade holder assembly.

In FIG. 2B the sensors 10 are located between the blade 21 and theholder 25. The sensors, in particular piezo sensors 10, transmitmeasurement information to a receiver 31, which transmits themeasurement information to a control system 32, which can directly orindirectly control the loading means of the blade holder assembly.

In FIG. 3 is schematically shown an example of the loading arrangementin a coater or a sizer. By reference number 30 is indicated a roll ofthe coater or of the sizer. Main loading devices 26 e.g., pistons, arelocated at each end of the frame structure 29. The assembly with the rodor the blade is attached to the frame structure by its rod-bed assemblyor blade holder assembly and is located in the view of FIG. 3 behind theframe structure 29 opposing the roll 30 such that when loaded the rod orthe blade are in loading pressure contact with the roll 30, i.e. fordosing the coating or sizing medium on the roll 30. To the framestructure 29 is attached a loading or support plate 28 extending in across direction, i.e. horizontally in the view of FIG. 3. The profilingloading means 27, for example spindles 27, are located to load theloading or support plate 28 in the cross direction. The profilingloading means 27 are thus located spaced apart in the cross direction.The sensors, in particular piezo sensors, transmit measurementinformation to a receiver 31, which transmits the measurementinformation to a control system 32, which can directly or indirectlycontrol the loading means 26, 27 of the rod-bed assembly.

Above the invention has been explained in view of some advantageousexamples only and many modifications in the examples and in the detailsof the examples are possible.

We claim:
 1. An assembly for a device for coating or sizing a paper or aboard web, the assembly comprising: a holder, having a front sidearranged to face a coating or sizing roll or a paper or a board web tobe coated, the holder having a back side opposite the front side; a rodor a blade supported on the front side of the holder; at least oneloading device engaged with the rod or the blade for loading the rod orblade in a direction away from the back side toward the coating orsizing roll or paper or board web; and load sensors located between therod or the blade, and the at least one loading device, for measuring theloading pressure on the rod or the blade locally.
 2. The assembly ofclaim 1 wherein the load sensors are piezo sensors.
 3. The assembly ofclaim 2 wherein the rod or the blade comprises a rod; and furthercomprising: an insert removably and insertably supported in a groove onthe front side of the holder, the insert having a front side arranged toface the coating or sizing roll or the paper or board web; wherein therod is rotatably supported in a recess on the front side of the insert;and wherein the sensors are located in between the insert and the holderon a side of the insert opposite the recess on the front side of theinsert.
 4. The assembly of claim 2 wherein the rod or the bladecomprises a rod; wherein the rod is rotatably supported in a recess onthe front side of the holder; and wherein the sensors are located on theback side of the holder for measuring pressure loading of the rod. 5.The assembly of claim 2 wherein the rod or the blade comprises a blade;further comprising: wherein the blade is supported on the front side ofthe holder; and wherein the sensors are located in between the blade andthe holder for measuring pressure loading of the blade.
 6. The assemblyof claim 5 wherein the at least one loading device comprises a loadinghose and wherein the sensors are located between the blade and theloading hose for measuring pressure loading of the blade.
 7. Theassembly of claim 2 wherein the at least one loading device comprises afirst loading device arranged to load the holder toward the coating orsizing roll or paper or board web, and further comprising: at least onesecond profiling loading device arrayed along the holder to profile theblade or rod; and wherein the sensors are located in the holder betweenthe rod or the blade and the at least one second profiling loadingdevice.
 8. The assembly of claim 2 wherein the load sensors comprise aplurality of load sensors arrayed and spaced apart in a cross directionof a web to be coated or sized.
 9. The assembly of claim 8 wherein theload sensors comprise a plurality of sensors each spaced apart a uniformdistance, so forming a band of sensors in the cross direction.
 10. Theassembly of claim 1 wherein the at least one loading device acts on therod or blade and the sensors located in a loading direction in line withthe rod or the blade, the loading direction defined by a direction inwhich the at least one loading device acts.
 11. The assembly of claim 1wherein the at least one loading device comprises a loading tube orspindles located on a side opposite the rod or the blade opposite thecoating or sizing roll or a paper or a board web to be coated.
 12. Amethod of coating or sizing a paper or board web with a rod or bladecomprising the steps of: loading the rod or blade against coating orsizing roll, or a paper or board web to be coated; wherein the rod orblade a holder is held in a front side of a holder the front side facingthe coating or sizing roll, or the paper or board web to be coated roll,so that the rod or a blade is supported on the front side of the holder;loading with a load, the rod or the blade in a direction toward thecoating or sizing roll, or the paper or a board web; sensing the loadwith piezo sensors located between the rod or the blade, and the load;and measuring a loading pressure on the rod or the blade, locally. 13.The method of claim 12 further comprising the steps of transmittingmeasurement information from the sensors to a receiver, and from thereceiver transmitting the measurement information to a control system;and controlling the loading the rod or the blade directly or indirectlywith the control system.
 14. The method of claim 12 further comprisingcontinuously measuring the loading pressure on the rod or the blade,locally.
 15. The method of claim 14 further comprising usingcontinuously measuring the loading pressure on the rod or the blade,locally for troubleshooting equipment or during a start-up.
 16. Themethod of claim 12 wherein the loading with a load, the rod or the bladein a direction toward the coating or sizing roll, or the paper or aboard web is adjusted manually or automatically based on across-directional profile of the loading pressure based on measuring theloading pressure on the rod or the blade, locally.
 17. A method ofupgrading an apparatus for coating or sizing a paper or board web with arod or a blade, the method comprising; installing load sensors locatedbetween a rod or a blade and at least one loading device, wherein therod or blade is supported on a front side of a holder, the front sidearranged to face a coating or sizing roll or the paper or board web, andthe at least one loading device is arranged engaged with the rod or theblade for loading the rod or blade in a direction toward the coating orsizing roll or paper or board web; measuring loading pressures on therod or the blade locally; and using an expert service to adjust loadingon the rod or the blade in a direction toward the coating or sizingroll, or the paper or board web based on the loading pressures asmeasured.